create multi geometries from vector of single geometries

[visr]

using LibGEOS, GeoInterface

# 3 overlapping circles in a triangle
circles = [
    buffer(Point(0.0, 0.0), 1.0),
    buffer(Point(1.0, 0.0), 1.0),
    buffer(Point(0.5, 1.0), 1.0),
]

# now if from these 3 polygons we want to create a single MultiPolygon
# you might expect this to work:
MultiPolygon(circles)
# but you get -> ERROR: LoadError: MethodError: no method matching MultiPolygon(::Vector{Polygon})
# going through the GeoInterface constructor works, but will be less efficient
MultiPolygon(GeoInterface.coordinates(circles))

LibGEOS.jl/src/geos_types.jl

Lines 81 to 95 in e1f2b25

	mutable struct MultiPolygon <: GeoInterface.AbstractMultiPolygon
	ptr::GEOSGeom
	function MultiPolygon(ptr::GEOSGeom)
	multipolygon = new(ptr)
	finalizer(destroyGeom, multipolygon)
	multipolygon
	end
	MultiPolygon(multipolygon::Vector{Vector{Vector{Vector{Float64}}}}) =
	MultiPolygon(createCollection(GEOS_MULTIPOLYGON,
	GEOSGeom[createPolygon(createLinearRing(coords[1]),
	GEOSGeom[createLinearRing(c) for c in coords[2:end]])
	for coords in multipolygon]))
	MultiPolygon(obj::T) where {T<:GeoInterface.AbstractMultiPolygon} = MultiPolygon(GeoInterface.coordinates(obj))
	end

This probably goes for all multi geometries, not just multipolygon.